Commentary & Opinion
12:17 pm
Fri August 17, 2012

David Nightingale - SSTs

Settling into my seat on an Airbus, I wished that the 8-hour return from Europe could be more like 3 1/2 hours, as I'd heard the SSTs used to take.

 Those SSTs -- Tupolevs and Concordes -- first flew in the late 60's. The Tupolev was first, in 1968, and then the Concordes in 1969. The latter went for 31 years without a crash – with the huge exception of the French Concorde that hit a piece of metal on the runway while taking off from Paris and crashed in flames, killing all on board.

 The cruising speeds of both makes of SST were 1330 mph – just over twice the speed of sound (or Mach 2) compared to the typical speeds of today's Jumbos and Airbuses, which is about 550 mph, and their cruising height was 60,000 ft as opposed to today's roughly 30,000 ft.

 Both the Concordskis and the Concordes weresimilar-looking, with swept-back wings, and droop noses so that the pilots could see the ground when they landed. Similar, yes, but the Concordski had parachutes to slow it upon landing, as opposed to Concorde's anti-lock brakes.

 Sadly, those Tupolevs suffered more than one crash, including a famous disaster at an Air Show in 1973.

 Supersonic flight has of course been in existence a long time, whether from a fast-moving whip, bullets, or the odd noise from a propeller if the tips are moving faster than sound. But it wasn't until 1947 that Chuck Yeager became the first person to break the sound barrier in the Bell X-1.

 16 airworthy Tupolevs were built. After they were no longer in service a wealthy US business-woman teamed with NASA and Boeing and they bought one for $350 million, turning it into a research lab. That Tupolev made about 27 flights, which were discontinued after 1997. The final commercial flight of a Concorde was in 2003.

 The engineering problems SST designers had to face were numerous. One of the most basic problems with any SST is that in order to reduce drag they must be bullet-shaped and narrow. Also, just as a piece of space debris burns up in air, the front of the SST actually reaches over the boiling point of water (despite external air temperatures of maybe  -70F.) This means that a 200-foot long SST going at 1330 mph has expanded over half a foot compared to its length on the runway! Also, the melting point of aluminum is only about 1200 F, and so if we go far beyond Mach 2  we have to turn to materials like titanium.

 Why were those SSTs not cost-effective? Instead of the wide fuselage of 8 seats across, with 2 aisles, as in the Airbus, the Concordes and Tupolevs only managed 2 seats on each side of a narrow aisle in their 9 foot diameter fuselages. Even so, for a while in the late 1980s a daily service to NY, and 3 times a week to Miami (via Dulles in Washington) and a winter service to Barbados, apparently did make a profit.

 Finally, one of the things people notice about SSTs is the sonic boom -- which annoyed Long Islanders enough to get the Concordes banned altogether between 1976-'77. What's happening? Well, just as the little waves in front of a boat get closer and closer and ultimately pile up on top of each other when the boat reaches the water-wave speed, forming a “V”-shaped wake that wets our feet as we stand on shore, so a jet's sound-waves pile up in front and the analogous wake (this time cone-shaped) reaches us with an analogous bang.

 So that summarizes just a few of the SST properties, and I'd like to add that I'm indebted, as is commonly the case, to Professor Tarun  Biswas, of SUNY, New Paltz, for many enlightening conversations on topics such as this.

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